Welcome to HVAC-Talk.com, a non-DIY site and the ultimate Source for HVAC Information & Knowledge Sharing for the industry professional! Here you can join over 150,000 HVAC Professionals & enthusiasts from around the world discussing all things related to HVAC/R. You are currently viewing as a NON-REGISTERED guest which gives you limited access to view discussions

To gain full access to our forums you must register; for a free account. As a registered Guest you will be able to:

Participate in over 40 different forums and search/browse from nearly 3 million posts.

How to know which HVAC guy is right

Hi all, and thanks in advance for any insight you offer.

I live in portland, Oregon. The house is currently 2550 sq feet. Has one unit to do the whole house.
Trouble is, the upstairs is always significantly hotter than the downstairs.
We will call this problem 1.
Problem 2 is that I would like to do an addition of about 500 sq ffet, mainly upstairs. But at the end of the house furthest from the unit, and I would like it heated and cooled.

I have talked to at least three hvac guys (each from a different contractor bidding the job). And they don't know what each other has suggested.

current setup... only one return, in the stairwell that goes upstairs at about the floor level for upstairs. Only one down stairs room is vaulted, and that vault doesn't open to the upstairs (there is actually a wall with windows from an upstairs room looking into the vaulted downstairs room) Temperature differential from the thermostat (downstairs) and the master bed room upstairs in the summer is about 5 degrees.

Guy 1 says he can just add vents to the existing system for the new rooms, and make the system a two zone system if I want to make it so they balance better.

Guy 2 says he can do the same as guy 1, but we need to add a return upstairs to get the balance we are looking for with the 2 zone system.

Guy 3 says he would have to add a unit in the attic to handle the addition, and unless we want to mess with the existing upstairs rooms so that the attic unit can manage them as well, we will need to add a return for the existing system upstairs and two zone that existing system.

needless to say it gets more expensive from guy 1 to guy 3.
But the apparent experience level of the guy increases as you go from 1 to 3.
And the amount of time they actually looked at what was there increased from guy 1 to 3. As well as time spent brainstorming about a solution.

So normally I would think guy 3 was trying to sell me more than I need. But the time and experience factors seem to imply that the other guys were just trying to get their contractor the job, and might not be concerned about the end product.

Air conditioning is just that air...conditioning. You must return air to the unit, condition it, and return it to the space. Pumping cold air into a space will not cool or dehumidify it. A the very least, it sounds like a return needs to be added upstairs with any additional run that might go in. With out more load calc data the rest is hard to say. But the second unit upstairs for the addition and to supplement the second floor would deff get you want you want which is comfortable upstairs. It may leave the downstairs unit oversized which could give you issues. zoning might be the way to go. A different way might be to do a mini split (ductless unit) for the addition. just some thoughts much more info is needed...

Well I don't think I really expect a direct answer. I am hoping for ideas on how to figure out the answer...

I am confident the 3rd guys solution would do the job, but the cost of it is at least $ more than the other solutions. And probably more like $ really. Which is like 150% more or so. This makes me think there should be some middle ground. And he seems dead set on the second unit. Hasn't even proposed a way to use the single unit even though he admits it has the capacity.
Also he seems hung up on what I think are simple things. Like the current supply for upstairs runs on the East side of the house, and sends ducts with the joists to the west side. The upper floor hangs out over the front port on the East side, and the supply is run above the porch. When talking about increasing the size of that supply, I suggested taking the ceiling of the porch down to access it. He said that wouldn't work, that we would have to open the walls from the inside of the house into that same space. But I can't see how that would be any different...
He also seemed to think that vents on the west side can't be moved one or two joists over... I think he means, can't be done without heading off a joist or two. But he doesn't say it that way. So it is hard to tell when he means "can't" versus he doesn't know if it can be, or he doesn't want to...

Ask each guy why the other guys ideas/way isn't better. They saw your house, not us.

Thats gonna be your best way to figure it out.

Tried that... I got the "I don't know what ... was thinking but what I am saying is this". Which really is the smart answer, you ain't lieing when you say you don't know what someone else was thinking...

Then get some more estimates. And see if any choose the same route as the first 3.

Well, if I call an HVAC guy he will realize that the contractor will use his own guy no matter what this guys says. So he has no reason to even come out.
Can I pay a guy for advice even if there is no job for him? And if so, what is a good amount to pay for advice?

We don't talk prices here. A designer would come out. but he won't be cheap.

I have a design for the addition... it's just a question of how to manage the hvac. So far the HVAC guys are free estimates since they are working for the contractor... I bet most HVAC guys don't even have many calls like this. So whoever I call isn't going to have a number either... what should I offer to start the ball moving?